An emission spectrum of an LED generally has a peak within a particular wavelength range, and the wavelength ranges on the short wavelength side and the long wavelength side of a particular wavelength range do not have an emission peak more than the measurement limit. In order to obtain a white light (natural light) in which an emission spectrum is distributed continuously and widely, lights having various wavelengths are combined so as to compensate for wavelength ranges which do not have an emission peak more than the measurement limit (FIG. 9 (cited from the Non Patent Literature 1)). However, there are countless wavelength ranges to be compensated for, and it is almost impossible to completely compensate. Therefore, it is difficult to obtain the light having a continuous emission spectrum like a white light by using a conventional LED.
Meanwhile, diamond having the highest dielectric breakdown electric field strength and thermal conductivity among semiconductor materials has been drawing new attention as a material for light-emitting devices. A spectrum of a light emitted by a light range and a visible light range.
However, a peak within a visible light range does not exist within a wavelength range corresponding to a red light, and is unevenly distributed within a wavelength range corresponding to a blue light. In other words, in a white light obtained by using a light-emitting device made of diamond, an amount of a red light component is insufficient relative to an amount of a blue light component. Therefore, regarding a light-emitting device made of diamond, it is difficult to obtain a white light with a high color rendering property which has a continuous light emission spectrum and is formed by uniformly containing respective light components of a visible light range.